Immunology and the cellular response to infection Flashcards

Question

What is the reason for inflammation?

Answer 1

Response to tissue damage or microbial invasion - Goals: Bring phagocytes to the injured area Isolate, destroy and inactivate invaders Remove debris Prepare subsequent healing

Answer 2

Blood phagocyte Short/half life / high turnover Multilobed nucleus Oxygen related killing – ROS, NADPH oxidase Express TLRs Undergo apoptosis

Answer 3

Resident phagocyte Last for weeks Killing is nitrogen related – RNS, iNOS Express TLR and produce cytokines Eat and clear bacteria and dead cells Monocytes are recruited to tissue differentiate into macrophages

Answer 4

Attachment Internalisation Degradation Exocytosis

Answer 5

Lymphocyte-like (no immunological memory) Very aggressive WBCs (5-15% total population) Requires cell-cell contact to functino Kill via release of perforins Pores form in cell membranes Results in cell lysis Target cancerous and virally infected cells

Answer 6

Recognise specific structures present on pathogens LPS Viral/bacterial genetic material Peptidoglycan Results in signalling cascade and transcription factor activation Production of: Proteins required for cell signalling/activation Interferons Proinflammatory cytokines eg TNF, IL-1

Answer 7

Soluble communication factors called cytokines and chemokines

Answer 8

* Small proteins (<25kDa) * Name means cell movement * Action can be autocrine,paracrine (chemotactic) orendocrine (pyrogenic) * Produced by a wide range of cells – Immune cells e.g.macrophages – Connective tissue e.g. epithelial cells * Can be pro or anti inflammatory

Answer 9

* Chemotactic cytokines – over 100 intotal * Two large families * Receptors – 7 TMD, G-protein coupled(GPCR). * Most of chemokines interact with multiple receptors, and most of receptors respond to multiple chemokines. * Subset specificity – IL-8 and neutrophils

Answer 10

Interferes with viral replication Enhances phagocyte activity of macrophages Stimulates production of antibodies Enhances the killing power of NK cells and cytotoxic T-lymphocytes Slows cell division and tumour growth Mode of action – virus protein synthesis is stopped, virus cannot multiply and dies

Answer 11

3 pathways of activation Classical Alternative Lectin All converge on terminal pathway Results in membrane attack complex (MAC) formation and cell lysis Also produces opsonin and chemoattractant

Answer 12

Antibodies Made by B-lymphocytes Detect bacteria and viruses Extracellular – interstitial fluid Ebola/COVID19 survivors – passive immunity

Answer 13

Friend from foe Bacteria, virus, fungus Toxin or diseases cell in body Act as flags to alert adaptive immune system

Answer 14

- develop and mature in bone marrow - develops ability to identify friend and foe (immuno-competatance, self tolerance) - 10,000 receptors on surface - each B cell has its own membrane bound receptor - overwhelming odds

Answer 15

1 – neutralisation 2 – opsonisation 3 – agglutination 4 - innate immune cell recruitment 5 – activation of complement system 6 – t-lymphocyte recruitment

Answer 16

Introduction of dead/modified antigen Secondary response is harder and faster Some disease eg measles are stable Some pathogens mutate eg flu

Answer 17

Introduction of antibodies from an immune donor – a temporary stop-gap

Answer 18

Physical barrier have failed Innate immunity has been overwhelmed Antibodies tried to keep your system healthy Pathogens still managed to invade cells T-lymphocytes are released

Answer 19

Cells decorate themselves with parts of the organisms they have destroyed Phagocytes that have engulfed a pathogen display part of the organism on proteins called MHCs on their surface Innate and adaptive cells can do this Professional and amateur antigen presenting cells

Answer 20

Diseased cells have modified peptides

Answer 21

Macrophages, dendritic cells and b cells MHC2 present exogenous peptides of pathogens they have engulfed Short amino acid sequences Important – heroes of the adaptive immune system cannot see whole pathogens

Answer 22

- made in bone marrow but mature in thymus - 2 main classes – CD4+ helper cells, and CD8+ cytotoxic cells

Answer 23

Helper T-lymphocytes call the shots CD4+ helper cells Cannot kill pathogens on their own Function as activators of other cells Naive helper T cells have receptors that identify a unique combination of MHC2 and peptide Activated CD4+s clone to helper and memory t-cells They raise the alarm via cytokines - Activates other CD4s – amplify the signal/response Activate CD8s

Answer 24

Cytokines from helper cells activate other T-lymphocytes Also finish activation of B-lymphocytes B-cell receptors are randomly generated, can be against self proteins B-cell interacts with protein, engulfs and presents the peptides – then it pauses T helper cells ‘inspects’ the B cell If CD4 binds B cell it releases cytokines and activates B cell leading to antibody production Otherwise B cell goes about its way and does not trigger immune response

Answer 25

Roam body looking for diseased cells Fragments of the very thing killing them displayed in MHC1 Cytotoxic cells can bind to MHC1 and peptide CD8s release enzymes that punch holes in disease cells (perforins, granzymes) Triggers apoptosis killing cell and pathogen inside

Answer 26

Subset of CD4+ cells Release inhibiting cytokines Prevents adaptive system from producing too many antibodies or cytotoxic cells that can cause damage to self

Answer 27

When immune system goes wrong Diabetes – insulin producing cells Rheumatoid arthritis – cartilage and bone Mutiple sclerosis – neural myelin Breakdown of immune regulation

Answer 28

Virus invades CD4 cells – reduces numbers

Immunology and the cellular response to infection Flashcards

(52 cards)